Hello, I have a 5977B (with 7890 GC) Extractor EI Source, one day it tuned to a repeller voltage of 0.5 when the previous tunes had been around 4. I've cleaned the source, and retuned and the Etune still gives me the low repeller voltage. The peaks when I run, have lower response. I've switched to an atune and that has resolved my peak issues, but I would still like a solution for the etune.